RE: Engine Mystery
Bruce,
Please define 'well' (in respect to the way you broke your engine in).
If you did it [link=http://www.rcuniverse.com/forum/Tapered%2DBore_Engine_Break%2Din_%2D_Upgraded/m_1850473/tm.htm]this way[/link] then you did do it well.
If you did it very rich, well...
Also, has the engine run a bit on the too lean side, on occasion?
The glow-plug in many engines will not run very well, after the break-in, due to FOD (break-in produces particles from the parts wearing in...), if it had not burnt out, that is.
Also, have there been adjustments, or weather changes? If the weather became warmer, or more humid, an adjustment change is necessary (which you did not write about doing).
Another thing; I believe your engine is a [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDXL5&P=ML]GMS .47[/link], not a GMS .46...
5 flights is too short for any change to happen, unless something wrong happened...